The present application relates to the transference of information over an airgap separating two members configured for relative rotation. It finds particular application in the context of computed tomography (CT) imaging applications, where at least one of a first data communication component or a second data communication component is located on a rotor and an airgap separating the first data communication component from the second data communication component is small (e.g., 20 mm or less). However, it may also apply to other applications, such as explosive detection machines, radar antennas, etc. where communication signals are wirelessly transferred.
Today, CT and other radiation imaging modalities (e.g., single-photon emission computed tomography (SPECT), mammography, projection radiography, etc.) are useful to provide information, or images, of interior aspects of an object under examination. Generally, the object is exposed to radiation comprising photons (e.g., such as x-rays, gamma rays, etc.), and an image(s) is formed based upon the radiation absorbed and/or attenuated by the interior aspects of the object, or rather an amount of photons that is able to pass through the object. Generally, highly dense aspects of the object absorb and/or attenuate more radiation than less dense aspects, and thus an aspect having a higher density, such as a bone or metal, for example, will be apparent when surrounded by less dense aspects, such as muscle or clothing.
Some radiation imaging modalities, such as CT, are configured to generate volumetric data corresponding to an object under examination. To generate this volumetric data, the CT imaging modality is typically configured to rotate a radiation source and a detector array about the object under examination (e.g., causing the object to be viewed from a plurality of angles). For example, the radiation source and/or the detector array may be mounted to a rotor, also referred to as a rotating gantry, configured for rotation relative to a stator, also referred to as a stationary unit.
Given that the radiation source and the detector array are mounted on the rotor, power and control information (e.g., instructing the radiation source and/or other electronic components how to operate) are typically supplied to the rotor from the stator. Moreover, imaging data (e.g., data generated in response to the detection of radiation by the detector array) and/or status information (e.g., indicative of a status of various components mounted to the rotor) are typically transferred from the rotor to the stator. It may be appreciated that the volume of data transferred, particularly with respect imaging data, may be quite large. For example, some imaging modalities may require transfer speeds of up to 5 gigabits per second (e.g., particularly if the rotor does not comprise a storage medium to temporarily store data until the data can be transferred).
Conventionally, slip-ring assemblies have been used to transfer power and/or information (e.g., control information, status information, and/or imaging data) between the stator and the rotor or more generally between a movable unit and a stator (or between two movable units) through the physical contact of two materials (e.g., via a sliding contact). For example, a slip-ring attached to the stator may comprise metal brushes that are configured to physically contact electrically conductive surfaces (e.g., metal brushes) comprised on a slip-ring attached to the movable unit, allowing power and/or information to be transferred between the stator and the movable unit.
While the use of slip-ring assemblies has proven effective for transferring power and/or information between a stator and a movable unit (e.g., such as a rotor) and/or between two movable units, conventional slip-ring assemblies may generate dust or particles (e.g., as metal brushes wear), may be unreliable (e.g., again as contact surfaces, such as metal brushes, wear), and/or may be noisy (e.g., as surfaces rub against one another), which may cause interference with some procedures (e.g., CT imaging). Other drawbacks of slip-ring assemblies may include cost and complexity of manufacture due to special materials and/or mechanical precision that may be required.
More recently, contactless assemblies have been devised to transfer the data (e.g., or electrical signals corresponding to the data) between the rotor and the stator. While such assemblies overcome many of the aforementioned drawbacks to a slip-ring assembly, the rotor and/or the stator may have a diameter of 5 feet or more and a contactless assembly may be disposed along a circumference of the rotor and/or stator. Given the length of these assemblies, the signal transmitted through a contactless assembly may experience a high degree of attention, which may cause signal distortion. In addition, these contactless assemblies may be more difficult to manufacture and/or may have higher manufacturing costs than conventional slip-ring assemblies.